 /*******************************************************************************
  * Copyright (c) 2005, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.navigator;

 import org.eclipse.core.runtime.IAdaptable;
 import org.eclipse.jface.viewers.ILabelProvider;
 import org.eclipse.jface.viewers.ITreeContentProvider;

 /**
  * The content extension represents the components of a <b>navigatorContent</b>
  * extension. These handles are managed by a content service
  * {@link INavigatorContentService}.
  *
  * <p>
  * There is one {@link INavigatorContentExtension} for each content service.
  * There is only one {@link INavigatorContentDescriptor} for each extension.
  * </p>
  *
  *
  *<p>
  * This interface is not intended to be implemented by clients.
  *</p>
  * @since 3.2
  *
  */
 public interface INavigatorContentExtension extends IAdaptable {

     /**
      *
      * @return The id attribute of the navigatorContent extension.
      */
     String getId();

     /**
      * There is one descriptor for all instances of a
      * INavigatorContentExtension.
      *
      *
      * @return A handle to the descriptor used to manage this extension.
      */
     INavigatorContentDescriptor getDescriptor();

     /**
      * Clients may choose to implement {@link ICommonContentProvider}, but are
      * only required to supply an implementation of {@link ITreeContentProvider}.
      *
      * @return The content provider defined by the <b>navigatorContent</b>
      * extension.
      * @see ICommonContentProvider
      * @see ITreeContentProvider
      */
     ITreeContentProvider getContentProvider();

     /**
      * The real underlying implementation may only support the
      * {@link ILabelProvider} interface, but a simple delegate is used when this
      * is the case to ensure that clients may anticpate an
      * {@link ICommonLabelProvider} interface.
      *
      * @return The content provider defined by the <b>navigatorContent</b>
      * extension.
      * @see ICommonLabelProvider
      * @see ILabelProvider
      */
     ICommonLabelProvider getLabelProvider();

     /**
      *
      * @return True if any class has been instantiated by this extension.
      */
     boolean isLoaded();

     /**
      *
      * @return The state model associated with this content extension.
      * @see IExtensionStateModel
      */
     IExtensionStateModel getStateModel();

 }
